1. Field of the Invention
The present invention relates to an optical recording medium, and more particularly, to a method and an apparatus for detecting land pre-pit address information recorded on an optical recording medium having wobble tracks.
2. Description of the Related Art
Recordable optical discs, such as DVD-R, DVD-RAM, DVD+RW, and DVD-RW, have a spiral track on which wobble signals are recorded. In the case of a DVD-RAM, user data is recorded on land tracks and groove tracks and address information is recorded on a separate header region. However, in the case of a DVD-RW/+RW, specific user data is recorded on groove tracks only and address information is recorded on land pre-pits. Here, the address information recorded on the land pre-pits is referred to as land pre-pit (LPP) data. LPP data is recorded in a mastering process to report a physical address on a disc to which a pickup is transferred in a recording process of user data.
According to a DVD-RW specification, even and odd positions are alternately arranged on land tracks for each frame in order to record LPP data. Generally, the LPP data is recorded on the even positions which are located at a period of two frames. However, when the LPP data has been recorded on an adjacent position of a neighboring track, the LPP data is recorded on a next odd position. A synch code for LPP data is designated by three bits, such as 111 for an even position and 110 for an odd position. Here, in the case of an address data, 101 is referred to as 1 and 100 is referred to as 0.
According to the DVD-RW specification, it is difficult to precisely detect LPP data, because the recording position of the LPP data is determined in a mastering process. However, the precise detection of the LPP data is one of the important elements for determining the quality of a recording apparatus. Therefore, the LPP data has to be precisely detected in order to efficiently perform a recording process of user data on a DVD-RW.